Awesome instructable, thank you so much!Regarding links, on the few instructions I've written, I just link to search-pages of the product, or product type - since links often gets dead, especially ebay-links and other similar sites. Just a tip :) Thanks a again, gonna use this one as soon as I have the time!

A faulty wire could certainly explain it, as well as a bugged clone can - might be both. Anyway, not stating you need an external supply, but I indeed did with this setup. Have you measured the current draw on the display?

I'm really not sure, but it might be related to the fact that I was using a nano clone (not genuine arduino), which might have a different voltage regulator, or maybe a partly broken one? I'm also considering if the lack of pull-up resistors on the i2c-line could be the reason, even thought when I changed PSU it worked fine.